Objectives/Hypothesis: To compare the aerodynamic differences around ostiomeatal complex between the convex side and concave side in patients with concurrent nasal septal deviation and chronic rhinosinusitis, and to explore the potential correlation between nasal septal deviation and chronic rhinosinusitis occurrence from the perspective aerodynamics. Study Design: Retrospective case series. Methods: Fifty-six patients with concurrent nasal septal deviation and chronic rhinosinusitis were recruited. Nasal septal deviation was divided into mild, moderate, and severe deviations according to deviation angle. Using computational fluid dynamics, indices such as maximal velocity, maximal turbulence kinetic energy, maximal wall shear stress, and minimal temperature around the ostiomeatal complex were calculated and compared between the convex side and concave side, and among patients with varying severities of deflection. Results: The proportion for mild, moderate, and severe deviations was 12.5%, 32.1%, and 55.4%, respectively. Significant differences for maximal velocity, maximal wall shear stress, maximal turbulence kinetic energy, and minimal temperature around the ostiomeatal complex between the convex side and concave side could be detected. No significant difference of aerodynamic characteristics around the osteomeatal complex could be detected with the increasing of deviation angles. The incidence for chronic rhinosinusitis in convex, concave, and bilateral sides was 16.1%, 25%, and 58.9%, respectively. Conclusions: From the aerodynamics perspective, both sides of nasal cavity have the potential to predispose the occurrence of chronic rhinosinusitis in patients with nasal septal deviation. The increased deviation angle did not aggravate aerodynamic disturbance around the osteomeatal complex. The contributing role of nasal septal deviation in the pathogenesis of chronic rhinosinusitis should not be emphasized in excess. Laryngoscope, 2012